Floating deck for liquid-storage tanks



March 13, 1928.

J. H. WIGGINS FLOATING DECK FOR LIQUID STORAGE TANKS Filed/March 26,1923 2 sheets-sheet 1 IN1/wrox l jj/FLS jf www f4 7' TO Rvs/5 x5 March13, 1928.

1,662,225 J. H. WIGGINS FLOATINGVDECK FOR LIQUID STORAGE TANKS FiledMarch 26, 1923 2 Sheets-$heet 2 IN1/5N TOR TTOENEVS Patented Mar. 13,192s.

UNITED STATES JOHN H. WIGGINS, 0F BARTLESVILLE, OKLAHOIQIA.

FLOATING DECK FOR LIQUID-STORAGE jTANKS.

Application led March 26, 1923. Serial No. 627,835.

This invention -relates to liquid storage tanks of the type thatcomprise a movable top or deck which ,floats upon and is supported bythe liquid in the tank, and is an,

improvement upon the floating deck described in my U. S. Patent No.1,493,091, 'dated May 6, 1924, which resulted from my application forpatent Serial No. 540,847, filed March 3, 1922.

One object of my present invention is to provide a tank ofthe generaltype above referred to for storing oil and other liquid, which is ofsuch construction that permanent gases mixed with the liquid pumped intothe tank Jvill not cause the liquid to be carried out of the tank andksplashed onto the floating deck.

Another object of my invention is to provide a tank for storing volatileliquids which is of such construction that the lire hazard and theevaporation losses are reduced to a minimum.

And still Yanother object of my invention is to provide a liquid storagetank which is ot such design that relatively great variations in thediameter of the tank, due to eX- pansion and contraction, will notinfluence or have any eifect on the eciency of the means that isemployed to close the space between the `floating deck and the side wallof thetank.

To this end I have devised a liquid storage means, which, brieflydescribed, consists of a tank provided with a cylindrical side wall, aBoating deck supported by the liquid in the tank and proportioned sothat it covers the major portion of the surface of said liquid, and anannular chamber between the peripheral edge oit said deck and the sidewall of the tank constructed so that gases mined with the liquid pumpedinto the tank will be trapped in said chamber, and subsequently allowedto escape trom same through restricted openings. The annular chamber andthe restricted openings just reterrred to are preferably of gas-tightconstruction, so as to reduce the re hazard and the evaporation lossesto a minimum. By'

gas-tight l mean substantially gas-tight when in normal operation. lt isobvious that when, for any reason whatever, the internal gas pressureexceeds the safe limit, the vents will open and the annular chamber'isno longer gastight. The outer side wall of said annular chamber isformed by a shoe arranged parallel to the side wall ot the tank with itslower edge portion submerged .in the liquid in the tank, and in order toprovide for a relatively great expansion and contraction' of the tank,said shoe is composed of segmental sections sustained by long hangerscarried by t-he loating deck and joined to each other and to thefloating deck by pieces of flexible material which are preferablysubstantially gas-tight and tire-proof. Another annular chamber, whichis open at its upper end,

the shoe is formed by the outside surface o above referred to, by theinner surface ot the side wall of the tank which extends parallel tosaid shoe and by the surface of the liquid in the tank. Said shoe is ofrelativoly great depth, so that the open annular chamber between saidshoe and the side wall of the tank will be comparatively narrow withreference to its height, so that the oil vapors which collect in saidchamber will remain at the lower end of said chamber, notwithstandingthe fact that the upper end of said chamber is open, due to the factthat oil vapors are about twice as heavy as air. l/Vith such aconstruction there is practically no circulation of air or vapor in thechamber referred to.

Figure 1 of the drawings is a top plan view of part of the variableperipheral portion of a oating deck for liquid storage tanks constructedin accordance with my present invention.

Figure 2 is a vertical sectional view, taken on the line 2-#2 of Figure1, looking in the direction indicated by the arrows.

Figure 3 is a vertical sectional view, taken on the line 3--3 of Figure2, looking in the direction indicated by the arrows.

Figure 4 is an enlarged vertical sectional view, taken on the line 4-4ot Figure 1, looking in the directiony indicated by the arrows.

Figures 5 and 6 are diagrammatic views, illustrating slightmodifications that ma be made in the deck without departing rom thespirit o my invention; and I Figure 7 is a detail sectional view,illustrating one way of producin gas-tight joints between the varioussections of the peripheral portion of a deck of the kind illustrated inFigure 6.

Referring to Figures 1 to 4 of the draw ings, A. designates the sidewall of a liquid storage tank and B designates the central body portionot a movable top or .deck that lll) fioat-s upon the liquid in the tank,said central body portion being imperforate and so proportioned that itcovers the major portion of the surface of the liquid in the tank. Theannular space between the side wall of the tank and the centlal bodyportion B of said deck is closed or protected from the atmosphere by aseal which is constructed in such a manner that it is capable ofexpanding and contracting sufiiciently to compensate for variations inthe relative position and dimensions of the deck and the side wall ofthe tank. In the form of my invention shown in Figures 1 to 5l, saidseal consists of the peripheral portion of the deck that is carried bythe central body portion B 0f the deck and which is preferably composedof a number of segmental shoe members C that bear against the inner sideof the side wall of the tank and horizontally-disposed elements D thatproject inwardly from said shoe niembers towards a vertically-disposedannular rim E on the central body portion B of the deck, the shoemembers C co-operating with each other to form an annular shoe arrangedparallel to the side wall of the tank in sliding engagement with sameand having its lower edge portion submerged in the liquid in the tank,as shown in Figure 4. The horizontally-disposed elements D that projectinwardly lfrom the shoe members C may be formed in various ways, so longas they are of such construction that they provide for the expansion andcontraction of the shoe formed by the members C and will also serve as aclosure for the annular space between the side wall of the tank and thevertical rim E on thefperiphery of the central body portion B of thedeck, that is gas tight, in that it is sufliciently tight to retard orprevent the infiltration of air into said space and also retard orprevent the free escape of gases or vapors from said space.

One of the novel features of my present deck consists of the means thatis used for supporting or carrying the variable peripheral portion ofthe deck. Preferably said means consists of hinged or pivotally mountedhangers or supports F mounted on the central body portion B of the deckand combined with the various sections of the variable peripheralportion in such a way as to provide for the radial movement of saidsections and insure the shoe members C remaining in parallelrelationship with the side wall of the tank. As shown in Figure 1, twohangers F are provided for each section of the peripheral portion of thedeck, each of said hangers consisting of a substantially elbow-shapedlever arranged with its vertical leg projecting upwardly from thecentral body portion B of the deck, and its horizontal leg projectingoutwardly to- Wards the side wall of the tank so as to overhang one ofthe sections of the variable peripheral portion o1 tue deck. The lowerend of the vertical leg of each of the hangers F is pivotally connectedat 1 to a bracket 2 on the annular rim E, and the horizontal leg of saidhanger is connected by a swinging link 3 or-other suitable pivotalconnection with the section of the peripheral portion of the deck withwhich it eofoperates, thereby permitting the sections of the peripheralportion of the deck to move radially without destroying the parallelrelationship between the shoe members C and the side wall of the tank.In view of the fact that the vertical legs of the hangers F arecomparatively long and are pivotally mounted on brackets that arearranged in close proximity to the portion of the deck which floats uponthe liquid in the tank, the sections of the deck carried by said hangersare capable of moving radially with only a slight rise and fall. Such aconstruction is inexpensive to manufacture and it is reliable inoperation, as there is very little possibility of any of the sections ofthe variable peripheral portion of the deck sticking in such a way as tointerfere with the radial movement of said sections. In order to holdthe annular shoe and the central body portion of the deck inapproximately concentric relation with each other and also insure thelower edge portions of the shoe members C remainingr in snug engagementwith the side wall of the tank, the annular rim E on the central bodyportion of the deck is provided with a plurality of spring-pressedplungers G- that bear against said shoe members, as shown in Figure 4.

As previously stated, it is immaterial, so far as my present inventionis concerned` what type or kind of horizontally-disposed elements D areemployed or used to form a closure for the annular space between theshoe members C and the rim E. In the form of my invention-shown inFigures 1 to 4, inclusive, each of the shoe members C is provided with ahorizontally-disposed plate D that projects inwardly from same and .lapsover the upper edge of the rim E on the central bod portion of the deck,the inner edge of saidplate being turned downwardly so as to form a dripflange 4, as shown in Figure 4. It is essential that substantiallygas-tight joints be formed between the adjacent shoe members C andhorizontally-disposed plates D and between said plates and the upperedge of the rim E on the central body portion B of the deck. so as toretard or prevent the free escape of gases or vapors that collect in theannular space between the rim E and the side wall of the tank and alsoto retard or prevent the infiltration of air into said space. In thedeck shown in Figures 1 to 4 each section of the variable peripheralportion is provided at one end with an angle-shaped metallic device Hthat forms a lateral extension on one end of said section which lapsover and slides upon the left hand end of the adjacent section of thevariable peripheral portion of the deck, and the joints etween saiddevices H and the sections of the deck on which they slide are protectedby llexible sealing devices I, as shown in Figure 2, which arepreferablygas-tight and fire-proof. Preferably each of the flexible sealingdevices I is composed of a Yplurality Aof layers of canvas or otherfabric, treated to make it impervious to gas, and permanently combinedwith angle-shaped attaching devices 5 which are secured by bolts orrivets 6 to the ,horizontally-disposed plates D and shoe members C oftwo adjacent sections of the peripheral portion of the deck. Such aconstruction permits the horizontally-dis.

posed plates D and the shoe members C to move relatively to each otherand it insures gasftight joints between said parts, as each section ofthe peripheral portion of the deck' shaped metal devices H which act asclosures` for the radially-disposed joints between the various sectionsof the peripheral portion of the deck. Moreover, as Asaid fabric jointprotecting devices I are combined with the relatively movable parts ofthe deck in such a way that no metallic parts rub against the same, saiddevices I will last for a long period. 'In the form of my inventionillustrated in Figure 4 I have shown a similar fabric gas tight sealingdevice I connected to the upper edgeV of the rim E and to the undersideof the horizontallyedisposed plates D for protecting the joint betweenthe said plates and rim, the device I being' formed preferably oftreated fabric and conne'cted to the rim E and plates D in such a waythat wbileit does not interfere with the movement of said platesrelativel to each other or radially vwith respect to tie rim E, it doeseffectively prevent the free and uncontrolled escape of gases or vaporsfrom the annular space between the rim E and the Y side wall of thetanko Instead of using horizontally-disposed metal plates D to close thespace between the shoe members C and the annular rim E on the centralbody portionBv of the deck, said space can be closed by ahorizontallydisposed, flexible, gas-tight means D formed of treatedfabric or the like connected at its outer edge to the shoe members C andat its inner edge to the upper edge of the rim E, as shown in Figure 5.

Another slight modification that can be made without departing from thespirit of my invention is illustrated in Figure t5, wherein the annularrim E on the intermediate portion vB of the deck is provided with anannular trough 7 that contains a liquid 8 which co-operates'with sealingdevices 9 that project downwardly from the underside of plates D whichproject inwardly from the shoe members C. Each of the plates D may beprovided with one or more segmental shaped, depending sealing devices 9that are submerged or partly submerged in the liquid 8 in the trou h 7on the rim E, said sealing devices 9 e ectively preventing gases fromescaping from the annular space between the rim E and the side wall ofthe tank through the joint between the upper edge of said rim and thehorizontally-disposed plates D. The radial joints between the plates Dand shoe members C may be protected in the manner previously describedin connection with Figures 1 to 4, and if desired, flexible gas-tightdevices 10 formed of treated fabric or the like can be connected tothesealing devices 9, as shown in Figure 7, so as to produce gas-tightjoints between the adjacent sealing devices 9. In other words, if theclosure for the annular` space between the side wall ofthe tank andd therim E on the central portion of the deck is formed byhorizontally-disposed plates prof vided on their under sides withdepending devices that are sealed bya body of liquid, liexible devices10 can be provided for joining the sealing devices 9 together in such away that gas cannot escape through 'the joints between the ends of same.

vDue to the fact that the seal arranged between the deck and the sidewall of the tank is constructed inthe form of an inverted trough-shapedchamber whose lower end is open and in direct communication with theinterior of the tank, any gases that bubble upwardly around the edge ofthe rim on the deck will become trapped in said inverted trough-sha edchamber, and any liquid that is entraine in said gases will separatefrom same before said gases are permitted to escape from said chamber,Athereby reducing to a minimum the possibility of liquid being Vcarriedout of the tank with gases that escape of the deck: is provided with anumber ofy outlets J equipped with liquid sealed closures K. Preferablyeach of said closures K is arranged in such a way that it is capable ofopening automatically whenever an abnormal pressure or pressure inexcess of a certain degree exists in the inverted troughshaped chamberthat constitutes the seal. As shown in Figure 4, each of the outlets Jis formed by a horizontally-disposed tubular member projecting inwardlyfrom the rim E and provided with a vertical discharge outlet that issurrounded by an annular well 1l which contains a liquid that will notevaporate rapidly. A hinged closure K is provided for said dischargeoutlet, which closure is equipped with a depending annular flange 1:2that dips down into the sealing liquid in the well l1. If an explosionoccurs in the tank, due to the accumulation ot a large quantity of gasesbetween the rim E and shoe C', one or more of the closures K orexplosion doors will be thrown upwardly by the force of the explosion,thereby establishing communication between the atmosphere and theannular space between the rim E of the deck and the shoe C whose loweredge portion is submerged in the liquid in the tank.

One other feature of the construction above described that adds greatlyto its commercial utility is the mounting of the shoe members C on thecentral body portion of the deck in such a wa that it is impossible forsaid shoe mem ers to move outwardly beyond a certain point, and thuscause the hangers for said shoe members to bind or fail to operateproperly in instances where the side wall of the tank is abnormally outof round, In the form of the invention shown in Figure 4 the dependingflanges 4 on the plates D co-operate with the upper edge of the rim E tolimit the outward movement of the shoe members C, and in the form of theinvention shown in Figure 5 the gastight fabric D that is connected tothe shoe members and to the upper edge of the rim E functions as a meansto limit the outward movement of the shoe members. Obviously, variousother means can be employed to attain this highly desirable result, andaccordingly, I wish it to be understood that so far as this feature isconcerned, it is immaterial what means is used to limit the movement ofthe shoe members outwardly away from the rim E, so long as said meansdoes not consist of the side wall of the tank, thereby insuring the shoemembers and their supporting hangers remaining in an operativecondition, even when the side wall of the tank becomes abnormally out ofround.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. A floating deck for liquid stora e tanks, comprising a central bodyportion t at normally floats upon the liquid in the tank, a variableperipheral portion for closing the space between said central bodyportion and the side wall of the tank comprising segmental shoe membersarranged with then' lower edge portions submerged in the liquid in thetank and having no direct connection with said central body portion,substantially the entire area of said shoe members being disposed inparallel relationshi with and in sliding engagement with the si( e wallof the tank, and means for sustaining or supporting,r said shoe membersfrom said central body portion constructed so as to permit relativemovement of said shoe members and body portion without destroying theparallel relationship between said shoe members and the side wall of thetank.

2. A floating deck for liquid storage tanks, comprising a central bodyportion that normally floats upon the liquid in the tank. a variableperipheral portion for closingr tbc space between said central bodyportion and the side wall of the tank comprising scgmental shoe membershaving portions arranged vertically in sliding engagement with said sidewall, pivotally mounted hangers on said central body portion, andpivotal connections between said shoe members and hangers that permitsaid hangers to move relatively to said central body portion withoutdestroying the parallel relationship between said shoe members and theside wall of the tank.

3. A floating deck for liquid storage tanks, comprising a central bodyportion provided with a vertically-disposed rim, a variable peripheralportion for closing the space between said rim and the side wall of thetank comprising segmental shoe members arranged in parallel relationwith the side wall of the tank and in sliding engagement with same,substantially elbow-shaped hangers pivotally connected at their lower'ends to said central body portion and having their horizontal portionsprojecting outwardly to- .wards the side wall of the tank, and swinginglinks carrying said shoe members and pivotally connected to thehorizontal portions of said hangers.

4. A floating deck for liquid storage tanks, comprising a central bodyportion provided with a rim, a variable peripheral portion for closingthe space between said rim and the side wall of the tank composed of aplurality of relatively movable sections separated from each other byradial gaps, pivotally mounted hangers on said central body portion thatcarry said sections, and flexible gastight sealing devices for closingthe gaps between said sections and between said sections and said rim.

5. A floating deck for liquid storage tanks, comprising a central bodyportion normally floating on the liquid in the tank and provided withanannular rim that is spaced away from the side wall of the tank, agastight closure for the annular space between said rim and the sideWall of the tank that is capable of expanding and contracting, and ameans for venting said annular space.

6. A floating deck for liquid storage tanks, comprising a central bodyportion normally floating on the. liquid in the tank and provided withan annular rim that is spaced away from the side Wall of the tank, aclosure for the annularl space between said rim and the side wall of thetank that is capable otl expanding and contracting, a gas outlet leadingfrom said annular` space, a closure for said outlet that is capable ofopening automatically in the event of an internal explosion in the tank,and a liquid seal for said closure.

7. A means for storing liquid, comprising a tank provided With a sideWall, a deck that normally floats on the liquid in the tank, a sealbetween said deck and the side Wall of the tank comprising shoes whichnormally contact with said side Wall, and flexible material combinedwith said shoes and with said deck so as to form an inverted trough,into which air cannot easily filter from the outside and out of whichaii` or vapor cannot escape easily to the outside.

8. A means for storing liquid, comprising a tank provided with a sideWall, a deck that normally floats on the liquid in the tank, and a sealbetween said deck and the side Wall of the tank constructed in the formof an inverted trough Whose lower end is open and in directcommunication With the interior of the tank.

9. A means for storing liquid, comprising a tank provided with a sideWall, a deck that normally floats on the liquid in the tank, and a sealbetween said deck and the side Wall of the tank constructed in the formot an inverted trough whose lower end is open and in directcommunication with the interior of the tank, .said inverted trough beingso constructed that air cannot easily filter into same from the outsideand air and vapor cannot escape easily from same to the outside.

l0. A means for storing liquid, comprising a tank provided With a sidewall, a deck that normally floats on the liquid in the tank, a sealbetween said deck and the side Wall of the tank constructed in the formof an inverted trough Whose lower end is open and in directcommunication with the interior of the tank, and means for relievingexcessive internal pressure in said inverted trough.

v ll. A means for storing liquid, comprising a tank provided With a sideWall, a deck that normally floats on the liquid in the tank and providedat its peripheral edge with a rim, shoes arranged in contact With theside wall of the tank, and means co-operating with said shoes and rim toforni an inverted trough that traps gases which bubble from beneath saidrim and prevents said gases from causing entrained liquids in same to besplashed onto the top surface of the deck.

' JOHN H. WIGGINS.

